1. Field of the Invention
The present invention relates to an input device to concentrate the operation of a plurality of electronic devices into one operating section and relates in particular to a force-feedback input device for feeding vibration back to the operating section.
2. Description of Related Art
In recent years automobiles have been provided with different types of electronic devices such as air conditioners, radios, television, CD players, and navigation systems. However operating the vehicle may become difficult while attempting to separately operate each of these electronic devices. To make actions such as turning the desired electronic equipment on and off and selecting functions simple without interfering with driving the vehicle, force-feedback devices of the related art were proposed so that by operating one operating element, a vibration unique to a specified operating position was fed back to the user.
A force-feedback device of this type in the related art is explained while referring to the drawings. FIG. 5 is a perspective view of the mechanism of the force-feedback device of the related art. FIG. 6 is a block diagram of the force-feedback device of the related art. FIG. 7 is a drawing illustrating the intermeshing of the gears.
An operating section 11 is connected to a shaft 12 and a bearing 13. The operating section 11 is capable of oscillating by way of the bearing 13. The bearing 13 is clamped to the case 14.
Two linkages 15, 16 are made of metal formed in an L shape. These linkages 15, 16 are installed at right angles to each other and have slotted holes 15a, 16a at one end. A shaft 12 is inserted through these slotted holes 15a, 16a. The linkages 15, 16 are moved by the oscillation of the shaft 12.
Two large gears 17, 18 are axially supported in mutually intersecting directions in a case 14. The large gears 17, 18 are fastened at the end opposite the end of the linkages 15, 16 having the slotted holes, and the linkages 15, 16 rotate as one piece along with the large gears 17, 18. The oscillation of the operating section 11 respectively rotates the large gears 17, 18 by way of the linkages 15, 16 according to the oscillating direction of the operating section 11.
The small gears 19, 20 intermesh with the large gears 17, 18 and are installed at right angles to each other. The small gears 19, 20 rotate faster (have a greater rotation quantity) than the large gears 17, 18.
The encoders 21, 22 rotate as one piece concentrically with the small gears 19, 20. The encoders 21, 22 output the rotation quantity in a direction at right angles to the small gears 19, 20. For example, the encoder 21 detects the rotation quantity in the X direction and the encoder 22 detects the rotation quantity in the Y direction. These rotation quantities detected in the X direction and Y direction can be substituted into X coordinates and Y coordinates for position information.
The motors 23, 24 rotate concentrically as one piece with the small gears 19, 20 and the encoders 21, 22. Therefore, oscillating the operating section rotates the small gears 19, 20, and the shafts of the encoders 21, 22 and the motors 23, 24 rotate along with this rotation. Conversely, when the motors 23, 24 are rotated minutely in forward or reverse, the operating section 11 oscillates minutely. A unique vibration from this oscillation is fed back to the operating section 11 as force-feedback.
The operation of the operating section 11 is next described while referring to the block diagram of FIG. 6. Oscillation of the operating section 11 rotates the encoders 21, 22 and position information is obtained by way of the X coordinates and Y coordinates. This position information is detected by the position signal detector 25 within the computer 24. The position signal detector 25 sends a table select signal according to this acquired position information to the table selector section 27a inside the CPU 27. The table selector section 27a using the table select signal, selects a corresponding table from the table 26a within the ROM 26 and sends this signal to the motor driver 28. After the collator 27b inside the CPU 27 checks whether or not the position information appended to the table is correct, the position information is sent at this time to the motor driver 28. Information conveying the rotational direction and size of the rotational torque of the motors 23, 24 is encoded and stored in the table 26. A drive signal is sent from the driver 28 to the motors 23, 24 and the motors 23, 24 are then driven by this drive signal. The operating section 11 in this way obtains force-feedback from the selected table by the driving of the motors 23, 24.
A problem occurs in this above method using two gears for conveying power from the motor to the operating section, because the extent of intermeshing between the two gears is different due to variations in the part dimensions. FIG. 7 is a concept view showing the gear intermeshing in the force-feedback device of FIG. 5. Here, one set of gears 19, 20 is axially supported by the motor drive shaft 29. The other set of gears 17, 18 is slaved to the other gears and rotates a gear bearing 30. In FIG. 7, when the gear intermesh clearance C is set to 1 millimeter and the inter-axial distance L is set to 30 millimeters as the design specification values, the gear diameter becomes larger due to variations in the gear parts and the gear intermesh clearance becomes 0 millimeters and the inter-axial distance L becomes 31 millimeters. (The inter-axial distance widens as a result of the gears mutually pushing against each other due to a larger gear diameter caused by variations in part dimensions.) In such cases, even if a fixed quantity of electrical current is made to flow in the motor, the gear intermesh was too tight so that the quantity of gear movement (rotation quantity) became smaller with respect to the fixed amount of electrical current. Conversely, when the gear diameter became smaller due to parts variations, and the inter-axial distance L became 30 millimeters and the clearance C became 1.5 millimeters, the quantity of gear movement (rotation quantity) became larger with respect to the fixed amount of electrical current.
Therefore, even if force-feedback input devices were made having transmission devices of the same structure, the problem occurred that the force-feedback that was fed back to the operating section was different in each product due to variations in parts dimensions in the transmission mechanism.